Bjorøy Tunnel
Overview | |
---|---|
Location | Øygarden and Bergen, Norway |
Coordinates | 60°20′15″N 5°11′03″E / 60.33750°N 5.18417°E |
Status | In use |
Route | Fv 5236 |
Start | Håkonshella |
End | Bjorøy |
Operation | |
Work begun | 29 September 1993 |
Opened | 7 May 1996 |
Operator | Norwegian Public Roads Administration |
Toll | Until 29 January 2005 |
Technical | |
Length | 2,012 m (6,601 ft) |
No. of lanes | 2 |
Lowest elevation | −88 m (−289 ft) |
Grade | 18% |
The Bjorøy Tunnel (
Specifications
The Bjorøy Tunnel is a subsea tunnel which runs below the Vatlestraumen strait between the island of Bjorøy and the mainland of Bergen. It carries two lanes of Norwegian County Road 5236. It is the only
Before the construction of the Bjorøy Tunnel, the geology of the area was thought to consist entirely of metamorphic basement rocks similar to those exposed on the surrounding islands. The
History
Planning
Since 1966, Bjorøy had been served by the Alvøen–Bjorøyhamn Ferry.[5] The plans for a tunnel to Bjorøy were first launched by the engineer Jack Jahnsen in 1980. These were based on the then under construction Vardø Tunnel, which became the first subsea tunnel in Norway when it opened in 1982.[6] He had a meeting at his place on 18 December 1980, to which the three municipal councilors from Bjorøy also were invited, where he tried to get support for the tunnel, which would be the topic of a municipal council meeting on 20 December. The council unanimously voted in favour of establishing a committee to look into the tunnel. The committee was established on 6 January 1981 and concluded with that there were three alternative possibilities to build a fixed link to Bjorøy: a bridge from the island over Søre Steinsundet via Vestre Steinsundholmen, Kjerringholmen and Kaggen to Søre Snekkevik on Litlesotra; a tunnel under Vatlestraumen to Håkonshella; or a bridge over Vatlestraumen to Håkonshella or Kongshaug.[7]
At the time, a bridge to Litlesotra was estimated to cost 111 million kr, a tunnel was estimated to cost 36 million kr, while a bridge over Vatlestraumen was estimated to cost 74 million kr. All three included a road connection to Tyssøy, with the bridge proposals costing 16 million kr for the Tyssøy connection, and the tunnel having a cost of 4 million kr, in part because the earthworks volume from the tunnel could be used to build a mole with a short bridge.[8] Seismology tests were done in August 1983, and they concluded that the ground had good conditions: the uncompacted material laid mostly only 1-meter (3 ft 3 in) deep, albeit at times as deep as 7 meters (23 ft).[9] The proposed tunnel crossing followed a mountain ridge, and the maximum depth was between 40 and 45 metres (131 and 148 ft), although the topography went steep down to those depths.[10]
The plans were presented to
However, Norges Skibshypotek had to withdraw, as it was not permitted to invest in non-shipping investments. Instead, a loan was taken in Bergens Skillingsbank. Four land-owners made a guarantee for NOK 9 million, with a judicial registration covering an area of 347 hectares (860 acres). They hoped that the value of their land would increase after the tunnel had been built. The same amount was also guaranteed by Fjell Municipality. Public grants were also secured, so the debt would be NOK 27 to 30 million.[13] The planning was done by Chr. F. Grøner, for which the municipality paid the costs. Statistics from the ferry showed that 26,400 cars and 93,902 people had taken it in 1986, which had grown to 40,400 and 121,000 in 1989. The estimates were for a 90% increase until 2000, given an opening in 2002.[14] A bid for the project was gathered from Selmer–Furuholmen, which gave a maximum price of NOK 55 million, given that construction started in 1989.[15]
On 12 December 1989, the committee sent an official offer to Hordaland Public Roads Administration whereby they, as a company under establishment, offered to fully finance the tunnel. The plans called for tolls of 51 kr for a car and an investment cost of NOK 47 million.
The plans were met with criticism from locals on the Bergen side where the tunnel would emerge. They stated that the plans had "cheap solutions" and had unnecessary negative impact on their local environment. This included the demolishing of a football field and lack of noise barriers.[18] Bergen Municipality demanded that the costs of a new field be paid for by the project, and that the tunnel be slightly extended. A new estimate was made, which increased the price by NOK 10.3 million; however, Hordaland Public Roads Administration protested, stating that it would give an inferior road technically, that the existing development plans permitted the construction, and that the noise would not exceed the permitted limits.[19] They concluded that should these demands remain, the increased costs would terminate the project.[20] On 16 November 1992, Bergen City Council voted to allow the tunnel, under the condition that the tunnel project financed a new football field. The decision was appealed by lawyers representing the local community, but this was rejected by Hordaland County Governor on 30 August 1993.[21]
Originally the
An agreement was made between the ministry, the tunnel company and the county municipality on 6 January 1994 to build the tunnel.[26] The company had the right to collect tolls for up to 15 years on fees dictated by the county municipality,[27] and would have to pay NOK 27 million for the tunnel, with the county paying for the rest of the costs. The construction would be the responsibility of Hordaland Public Roads Administration, with the tunnel company only responsible for their part of the financing and the collection of tolls.[28] An agreement was made with Selmer, whereby they would charge NOK 59,422,500 and take the risk of the project, including any expenditures for unknown geological conditions or similar costs increases. They were also responsible for an insurance to reclaim the investments should it be proven impossible to build the tunnel.[29]
Construction
The construction of the tunnel started on 29 September 1993,[29] with the original plans calling for the tunnel to open on 15 June 1995.[28] The original construction consisted of blasting from Bjorøy, but by January 1994 there were problems with water leaks through cracks. The contractor described these as "common problems" when building tunnels, but that construction would be delayed by up to two weeks. To keep up with the schedule, the company started also blasting from the mainland.[30] However, the problems increased, and by September the tunnel was leaking 600 liters (130 imp gal; 160 U.S. gal) per minute, which was 50% more than estimated. This caused extra work to be done on the exterior to the tunnel, and costs had increased by several tens of millions of kroner. In particular, a different type of rock had been struck, and 60 tonnes (59 long tons; 66 short tons) of concrete had been injected without this giving the desired effects.[31]
On 30 September, Selmer stopped construction from the Bjorøy side, although it continued from the mainland.[32] About 750 metres (2,460 ft) from the Bjorøy side, the construction found a section of sandstone, the upper Jurassic Bjorøy formation,[4] a condition that had never been encountered during subsea tunnel construction before. Geological engineers stated that there was no known solution to overcoming the problem, and that if the contractor had blasted into the area, the tunnel would have been filled with sand and water within minutes.[33]
On a meeting on 10 October, O. T. Blindheim, a geological consulting company, and Selmer presented three alternatives: continued injection of cement, recommended by Blindheim; freezing, recommended by Selmer because it was the cheapest, but would take more time; and use of a water-tight shield. A technical committee was established, and on 16 December they recommended the use of cement injection combined with a ring of drainage holes around the tunnel before blasting.
Tolls and auxiliary roads
The grants were only given for the tunnel to Bjorøy, and not for the necessary roads that would connect Tyssøy to Bjorøy. This caused local controversy, as some people on Bjorøy disagreed that the tolls on the Bjorøy Tunnel should pay for the Tyssøy Bridge. On 13 May 1993, the costs of the connection to Tyssøy were estimated at NOK 5 million. The issue was not resolved when the construction of the tunnel started.[38] The original costs for the bridge were for NOK 11.4 million, including a 20-metre-long (66 ft) bridge with a clearance of 10 meters (33 ft). This was later reduced to 10 metres (33 ft) length and 5 meters (16 ft), which reduced the costs to NOK 9.4 million. Of this, the county paid NOK 4 million, while the two municipalities had advanced the transporting earthwork from the tunnel to the sound. On 22 January 1996, the tunnel company agreed to advance the construction costs and collect it from the tolls, with Sund Municipality guaranteeing for the debt.[39]
On 2 February 1996,[40] the tunnel company had an agreement with Bru og Tunnelskelskapet, which operates the Bergen Toll Ring, to collect the tolls in the tunnel using the Autopass automatic toll collection system. A manual collection system was estimated to cost NOK 1.4 million per year, while an automated system was estimated at NOK 0.4 million.[41] The tunnel opened on 7 May 1996, the same day the last ferry ran.[42] Originally the plan was to charge tolls similar to the ferry. With a manual system, it would not be possible to charge for two-wheeled vehicles and passengers, so the fares for other vehicles were raised slightly. In 1995, it had cost NOK 44 for a single passing with a car on the ferry. The tolls were set to NOK 120 for all types of vehicles, except two-wheelers, and NOK 72 was charged per travel with pre-paid ticket books. Bus riders had to pay for two extra zones. The toll plaza was open a few hour each week to allow people to purchase discounted tickets.[43]
The contract for the construction of the bridge to Tyssøy was announced on 20 August 1996,
On 19 January 2004, the freight ship Rocknes ran aground on the unmarked
References
- ^ "Folk flytter fra øyene tross milliarder til bru". NRK (in Norwegian). Retrieved 9 April 2013.
- ^ Pedersen, Frode (19 August 2003). "Tunneler bryter nye EU-krav". Aftenposten (in Norwegian). p. 3.
- ^ Styve, Kyrre (16 January 2010). "Vil ha mobilnett". VestNytt (in Norwegian). p. 5.
- ^ a b Bøe, R.; Fossen, H.; Smelror, M. (2010). "Mesozoic sediments and structures onshore Norway and in the coastal zone" (PDF). Norges geologiske undersøkelse Bulletin. 450: 15–32. Retrieved 18 January 2011.
- ^ Jahnsen 2006, p. 17
- ^ Jahnsen 2006, p. 21
- ^ Jahnsen 2006, p. 22
- ^ Jahnsen 2006, pp. 23–24
- ^ Jahnsen 2006, p. 24
- ^ a b Jahnsen 2006, p. 25
- ^ Jahnsen 2006, p. 26
- ^ Jahnsen 2006, p. 27
- ^ Jahnsen 2006, p. 28
- ^ Jahnsen 2006, p. 31
- ^ a b Jahnsen 2006, p. 30
- ^ Jahnsen 2006, p. 29
- ^ Jahnsen 2006, p. 33
- ^ a b Jahnsen 2006, p. 34
- ^ Jahnsen 2006, p. 35
- ^ Jahnsen 2006, p. 36
- ^ Jahnsen 2006, p. 38
- ^ Jahnsen 2006, p. 42
- ^ Jahnsen 2006, p. 43
- ^ Jahnsen 2006, p. 39
- ^ Jahnsen 2006, p. 41
- ^ Jahnsen 2006, p. 51
- ^ Jahnsen 2006, p. 50
- ^ a b Jahnsen 2006, p. 48
- ^ a b Jahnsen 2006, p. 52
- ^ Jahnsen 2006, p. 56
- ^ Jahnsen 2006, p. 57
- ^ Jahnsen 2006, p. 58
- ^ Jahnsen 2006, p. 60
- ^ Jahnsen 2006, p. 61
- ^ Jahnsen 2006, p. 62
- ^ Jahnsen 2006, p. 63
- ^ Jahnsen 2006, p. 64
- ^ Jahnsen 2006, p. 45
- ^ Jahnsen 2006, p. 46
- ^ Jahnsen 2006, p. 70
- ^ Jahnsen 2006, p. 71
- ^ Jahnsen 2006, p. 69
- ^ Jahnsen 2006, p. 72
- ^ Jahnsen 2006, p. 86
- ^ Jahnsen 2006, p. 87
- ^ Jahnsen 2006, p. 88
- ^ Jahnsen 2006, p. 75
- ^ Jahnsen 2006, p. 76
- ^ Jahnsen 2006, p. 81
- ^ Kalgraf, Marit (21 January 2005). "Bom stopp for bompengar". VestNytt (in Norwegian). Archived from the original on 15 January 2011. Retrieved 15 January 2011.
- ^ Holte, Magnus Aamo (8 May 2012). "Sjøvann renner rett ned i veibanen". Bergens Tidende (in Norwegian). Archived from the original on 10 May 2012. Retrieved 11 May 2012.
- Bibliography
- Jahnsen, Jack (2006). Fastlandssamband for Bjorøy og Tyssøy (in Norwegian). Straume: Fastlandssambandet Tyssøy – Bjorøy. ISBN 82-303-0642-7.